ABSTRACT
Sedimentary rocks record the environments in which they were deposited-perhaps a warm, shallow sea or a desert. By looking at the sequence of rocks built up in a place over a period of time, we can see how the environment has changed there over the millennia and work out details of Earth history. However, one particular rock type is rarely indicative of one unique environment. Mudstones, for example, can form in shallow lakes or in the deep sea; sandstones may form in deserts or on the beach so we cannot jump from the observation of simple rock types to instant identification of depositional environments.
